This invention relates to a tray for holding a stack of sheets of paper or other print media for feeding into a printer, For convenience, the term xe2x80x9cpaperxe2x80x9d throughout this specification is to be understood as encompassing all forms of print media including paper, plastic transparency sheets, vellum, and the like which are storable in a tray for feeding into a printer.
Paper trays associated with printers and having relatively adjustable side members, which act as paper guides, for accommodating different paper widths are known. At least one such paper guide is usually slidably mounted on the tray for movement towards or away from the other to vary their spacing, the slidable mounting being such that the paper guide is xe2x80x9cstifflyxe2x80x9d movable across the tray so that it will remain in position against the side edge of a stack of papers. That is, there needs to be a relatively high degree of frictional resistance to movement of the paper guide once positioned against a stack for it to function properly as a guide. However if this frictional resistance is too high, it becomes very difficult to adjust the paper guide on the tray, particularly given that very small width adjustments may have to be made. Thus a balance has to be struck between a user friendly ease of adjustment criterion and an opposing operational requirement. Unfortunately this balance is often such that the adjustable paper guide very gradually gets pushed away from the side edge of the stack of papers during the printing of numerous sheets. This is due to a side thrust force generated by a paper sheet as it enters into the feed trough of a printer prior to printing. Eventually a sufficient gap may develop between the side edge of the paper stack and the paper guide as to not prevent skewing of paper sheets as they are fed into the printer.
An object of the present invention is to provide a paper tray having an adjustable paper guide which cannot move away from a selected adjustment position on the tray and yet is readily adjustable between selected adjustment positions.
According to the present invention there is provided a tray for holding a stack of sheets of paper for feeding into a printer, the tray including a bottom support and two side paper guides at least one of which is adjustable relative to the other to vary a spacing between the two paper guides for accommodating different paper widths, the at least one adjustable paper guide being slidably mounted on the tray and having releasable means normally engaging said bottom support for locking said at least one paper guide in selectable positions thereon.
Thus the invention provides for a paper guide to be locked to the tray at a selected adjustment position. This is achieved by a means on the paper guide which in its normal position engages a surface of a bottom support of the tray. This means is releasable and when so released and held in its released position, the paper guide is readily slidable across the tray for movement to another selected position, whereat the releasable means is released for it to again engage and thus lock the paper guide in position.
Preferably the releasable means includes a detent or protrusion for engaging within a complementary means, such as one of a number of spaced indentations or recesses in the bottom support of the tray. The detent or protrusion may be a tooth for engaging a rack which is toothed thereby providing the spaced indentations. This rack may comprise closely spaced teeth such that with a complementary sized tooth and the releasable locking means, the paper guide can be adjusted by a very small amount. Preferably the releasable means includes a member mounted on the paper guide which has the protrusion or tooth depending therefrom. This member is preferably resiliently biased relative to the paper guide such that the protrusion or tooth normally engages one of the indentations in the bottom support surface of the tray and which may be provided by the above described rack. Preferably this member is pivotally mounted on the paper guide and acts as a lever whereby an upper portion thereof is manually pivotal towards the paper guide against a resilient bias to disengage the protrusion or tooth from an indentation in the rack in the bottom support surface of the tray. Thus an operator is enabled with one hand to release the locking means and hold it in a released position whilst sliding the paper guide to another selected position to make an adjustment to accommodate a different paper width in the tray. When the locking means is released, it automatically re-engages the complementary means of the bottom support surface of the paper tray to again lock the paper guide in position.
Preferably the adjustable paper guide further includes a resilient bearing member which is positioned thereon such that it engages a side edge of a stack of paper sheets within the tray to substantially prevent a sheet from skewing as it feeds into a printer from the paper stack.